-LRB- CNN -RRB- -- The rapid thud-thud-thud of military choppers overhead on Wednesday was the first thing to catch the attention of the residents of Cuernavaca , a city south of Mexico City known as a retreat for city-dwellers and tourists alike .

The helicopters landed near Punta Vista Hermosa , a majestic resort where condos sell for millions of Mexican pesos , and before long , seemingly hundreds of military personnel were on its grounds .

A few hours later , a ferocious firefight broke out between the military and a cell of drug traffickers .

`` Things like this rarely happen here , '' said Yadira Abigail Flores Delgado , who works at a nearby private security firm . `` I could hear the shots and the helicopters . It was a very ugly incident . ''

The outcome , however , was sweet for the administration of President Felipe Calderon .

In a strong blow to one of Mexico 's most notorious drug cartels , Mexico 's navy killed Arturo Beltran Leyva , head of the Beltran Leyva cartel and one of Mexico 's three most wanted criminals .

Six other cartel members and one naval petty officer also died in the raid . Three other people were arrested .

The end of Beltran Leyva 's reign at the helm of the violent cartel was hailed by Mexico and the United States as a major victory for Calderon 's offensive against the cartels , a war that has claimed more than 14,000 lives since 2006 . More than 7,300 people have been killed in drug-related violence this year , according to a tally by Mexico 's El Universal newspaper .

`` This action represents a major achievement for the people and government of Mexico , and is a decisive blow against one of the most dangerous criminal organizations in Mexico , '' Calderon said , speaking from the U.N. Climate Change Conference in Copenhagen , Denmark .

The U.S. Drug Enforcement Administration said that its cooperation with Mexico played a role in Wednesday 's action .

'' -LSB- Beltran Leyva 's -RSB- death has dealt a crippling blow to one of the most violent cartels in the world , and it comes as a result of significant cooperation and information sharing between law enforcement in the United States and our courageous partners in Mexico , '' DEA Acting Administrator Michele M. Leonhart said in a written statement .

Video footage of the condo where Beltran Leyva was staying revealed bullet-ridden walls . A plate of eggs and ham was set at the dinner table , which was adorned with two fruit bowls . A large baggie containing a white substance was nearby .

On Thursday , authorities presented to the media two women and a man who were arrested in the raid . Their role with the cartel was not made clear .

The women were identified as Catalina Castro Lopez and Gabriela Vega Perez . The man 's name was not immediately released .

It was believed that the raid was linked to another operation last week .

On December 11 , the navy got into a firefight in Cuernavaca with gunmen of the Beltran Leyva cartel . Three of the gunmen were killed and 11 were arrested , according to the navy .

Calderon said Wednesday 's operation `` was the result of an intense intelligence effort by the Mexican navy . ''

`` We 've never seen anything like this , '' Flores Delgado said . `` Everyone is scared . ''

The fear was palpable at a children 's hospital right behind the complex where the drug lord was killed .

Three military personnel posted themselves inside the hospital hours before the shooting started , saying only that they were in the middle of an operation , said Dr. Antonio Villa Montiel .

The shooting started just after 8 p.m. and lasted for about an hour and a half , about 30 minutes of which were very intense , Villa Montiel said .

`` There was gunfire , machine gun fire and grenades , some of it very close to the hospital , '' he said . `` Inside the hospital there was much stress , fear and anxiety . Some people even panicked . ''

Three navy personnel were wounded by hand grenades , one fatally , the navy said .

Navy 3rd Petty Officer Melquisedet Angulo Cordova died while being treated for his injuries , navy spokesman Adm. Jose Luis Vergara said . One of the other two navy men was in serious condition and the other was in stable condition , Vergara said .

`` It 's a battle won , but by no means the war , '' said Tony Payan , associate professor of political science at the University of Texas-El Paso .

The death of the leader of a major drug cartel is a victory for the government , but it could also spur more violence , said Payan , an expert on drug trafficking in Mexico .

For such a high-level blow by the military , reprisal killings by the cartel are a possibility , Payan said .

Violence could also flare from within the Beltran Leyva organization itself , as its lieutenants jockey for position in the inevitable reorganization .

Finally , rivals -- and maybe even allies -- of the cartel may fight for a piece of the organization 's lucrative smuggling routes , Payan said .

Beltran Leyva and his organization rose in the Pacific state of Sinaloa , home to a powerful cartel of the same name .

Beltran Leyva and his brothers initially were allied with the Sinaloa cartel , headed by Joaquin `` El Chapo '' Guzman . A series of disputes over the past years , however , led the Beltran Leyva brothers to turn on El Chapo , or `` shorty , '' and they have been most recently linked with Los Zetas , another violent cartel opposed to the Sinaloa group .

One of the Beltran Leyva brothers , Alfredo , was arrested by Mexican authorities last year and remains imprisoned . Another brother , Hector , was indicted on drug trafficking charges out of New York and Washington . The slain brother , Arturo , was also named in those indictments .

The Beltran Leyva cartel is known for air transportation expertise , Drug Enforcement Administration spokesman Michael Sanders said .

An estimate from two years ago said the group smuggled 300 to 400 kilograms of cocaine monthly into the United States , Sanders said . The group is also known to smuggle black tar heroin .

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Earlier this month , the U.S. Treasury Department added Hector Beltran Leyva and other top cartel figures to a list of `` specially designated narcotics traffickers , '' a move that freezes any assets they have under U.S. jurisdiction and prohibits people in the United States from conducting business with them . Arturo Beltran Leyva was already identified as a kingpin in May 2008 .

In the most recent addition , the U.S. government named 22 members of the Beltran Leyva organization and 10 related companies .

Since taking office , Calderon has made fighting the drug cartels a priority . More than 40,000 troops have been deployed throughout the country to help small and often corrupt local forces .

But it was the navy that made one of the biggest busts in the war on drugs .

The reason may be because after years in the field , the army was not as reliable as a fresh force .

`` Calderon has finally understood two things : that the army is susceptible to corruption , and that the army is not sufficient , '' Payan said .

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Arturo Beltran Leyva was one of Mexico 's three most wanted criminals

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Beltran Leyva and his brothers rose in the Pacific state of Sinaloa

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Six other cartel members and one naval petty officer also died in the raid